Java example source code file (LightweightContent.java)

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Java - Java tags/keywords

awt, gui, jcomponent, lightweightcontent, swing

The LightweightContent.java Java example source code

/*
 * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package sun.swing;

import javax.swing.JComponent;
import java.awt.Cursor;

/**
 * The interface by means of which the {@link JLightweightFrame} class
 * communicates to its client application.
 * <p>
 * The client application implements this interface so it can response
 * to requests and process notifications from {@code JLightweightFrame}.
 * An implementation of this interface is associated with a {@code
 * JLightweightFrame} instance via the {@link JLightweightFrame#setContent}
 * method.
 *
 * A hierarchy of components contained in the {@code JComponent} instance
 * returned by the {@link #getComponent} method should not contain any
 * heavyweight components, otherwise {@code JLightweightFrame} may fail
 * to paint it.
 *
 * @author Artem Ananiev
 * @author Anton Tarasov
 * @author Jim Graham
 */
public interface LightweightContent {

    /**
     * The client application overrides this method to return the {@code
     * JComponent} instance which the {@code JLightweightFrame} container
     * will paint as its lightweight content. A hierarchy of components
     * contained in this component should not contain any heavyweight objects.
     *
     * @return the component to paint
     */
    public JComponent getComponent();

    /**
     * {@code JLightweightFrame} calls this method to notify the client
     * application that it acquires the paint lock. The client application
     * should implement the locking mechanism in order to synchronize access
     * to the content image data, shared between {@code JLightweightFrame}
     * and the client application.
     *
     * @see #paintUnlock
     */
    public void paintLock();

    /**
     * {@code JLightweightFrame} calls this method to notify the client
     * application that it releases the paint lock. The client application
     * should implement the locking mechanism in order to synchronize access
     * to the content image data, shared between {@code JLightweightFrame}
     * and the client application.
     *
     * @see #paintLock
     */
    public void paintUnlock();

    /**
     * {@code JLightweightFrame} calls this method to notify the client
     * application that a new data buffer has been set as a content pixel
     * buffer. Typically this occurs when a buffer of a larger size is
     * created in response to a content resize event. The method reports
     * a reference to the pixel data buffer, the content image bounds
     * within the buffer and the line stride of the buffer. These values
     * have the following correlation.
     * <p>
     * The {@code width} and {@code height} matches the size of the content
     * (the component returned from the {@link #getComponent} method). The
     * {@code x} and {@code y} is the origin of the content, {@code (0, 0)}
     * in the coordinate space of the content, appearing at
     * {@code data[y * linestride + x]} in the buffer. All indices
     * {@code data[(y + j) * linestride + (x + i)]} where
     * {@code (0 <= i < width)} and {@code (0 <= j < height)} will represent
     * valid pixel data, {@code (i, j)} in the coordinate space of the content.
     *
     * @param data the content pixel data buffer of INT_ARGB_PRE type
     * @param x the x coordinate of the image
     * @param y the y coordinate of the image
     * @param width the width of the image
     * @param height the height of the image
     * @param linestride the line stride of the pixel buffer
     */
    public void imageBufferReset(int[] data,
                                 int x, int y,
                                 int width, int height,
                                 int linestride);

    /**
     * {@code JLightweightFrame} calls this method to notify the client
     * application that the content image bounds have been changed within the
     * image's pixel buffer.
     *
     * @param x the x coordinate of the image
     * @param y the y coordinate of the image
     * @param width the width of the image
     * @param height the height of the image
     *
     * @see #imageBufferReset
     */
    public void imageReshaped(int x, int y, int width, int height);

    /**
     * {@code JLightweightFrame} calls this method to notify the client
     * application that a part of the content image, or the whole image has
     * been updated. The method reports bounds of the rectangular dirty region.
     * The {@code dirtyX} and {@code dirtyY} is the origin of the dirty
     * rectangle, which is relative to the origin of the content, appearing
     * at {@code data[(y + dirtyY] * linestride + (x + dirtyX)]} in the pixel
     * buffer (see {@link #imageBufferReset}). All indices
     * {@code data[(y + dirtyY + j) * linestride + (x + dirtyX + i)]} where
     * {@code (0 <= i < dirtyWidth)} and {@code (0 <= j < dirtyHeight)}
     * will represent valid pixel data, {@code (i, j)} in the coordinate space
     * of the dirty rectangle.
     *
     * @param dirtyX the x coordinate of the dirty rectangle,
     *        relative to the image origin
     * @param dirtyY the y coordinate of the dirty rectangle,
     *        relative to the image origin
     * @param dirtyWidth the width of the dirty rectangle
     * @param dirtyHeight the height of the dirty rectangle
     *
     * @see #imageBufferReset
     * @see #imageReshaped
     */
    public void imageUpdated(int dirtyX, int dirtyY,
                             int dirtyWidth, int dirtyHeight);

    /**
     * {@code JLightweightFrame} calls this method to notify the client
     * application that the frame has grabbed focus.
     */
    public void focusGrabbed();

    /**
     * {@code JLightweightFrame} calls this method to notify the client
     * application that the frame has ungrabbed focus.
     */
    public void focusUngrabbed();

    /**
     * {@code JLightweightFrame} calls this method to notify the client
     * application that the content preferred size has changed.
     */
    public void preferredSizeChanged(int width, int height);

    /**
     * {@code JLightweightFrame} calls this method to notify the client
     * application that the content maximum size has changed.
     */
    public void maximumSizeChanged(int width, int height);

    /**
     * {@code JLightweightFrame} calls this method to notify the client
     * application that the content minimum size has changed.
     */
    public void minimumSizeChanged(int width, int height);

    /**
     * {@code JLightweightFrame} calls this method to notify the client
     * application that in needs to set a cursor
     * @param cursor a cursor to set
     */
    default public void setCursor(Cursor cursor) { }
}